Preparation And Visible Photocatalytic Property Of CuGaS₂-ZnS Nanoheterostructures

Currently,cadmium chalcogenides have been found to exhibit outstanding hydrogen production ability under visible light irradiation,and attracted most intensive investigations.However,owing to the ionicity of Cdu,?such catalysts suffer considerable hydrolysis,resulting in instability of the catalyst and heavy metal pollution in water solution.Searching other visible light active photocatalysts with weaker hydrolysis is therefore highly desired.CuGaS2-ZnS nanoheterostructures were successfully prepared through co-precipitation route.In a typical photocatalytic test,photocatalyst was dispersed in deionized water containing Na2SO3 and Na2S as hole scavengers.The main results andconclusions can be summarized as follows:Cu1.94S-ZnS dimeric nanoheterostructures are fabricated by employing Cu1.94S nanocrystals.The strategy for synthesizing CuGaS2-ZnS nanoheterostructures were presented by employing Cu1.94S-ZnS nanocrystals;the nanocrystals are monodisperse with uniform zigzag-like shape.The conversion from Cu1.94S to CuGaS2 follows the"catalyst-scarifying assisted hetero-growth" mechanism,in which Cu1.94S nanocrystals act not only as a "reactant",but also as a "catalyst",allowing Ga cations in solution to diffuse into Cu1.94S lattice and react with the Cu1.94S host there.CuGaS2 generates at the Cui.94S-ZnS interface since the defects induced by lattice mismatch provide active nucleation sites for CuGaS2.There are remarkable absorptions for CuGaS2-ZnS heterostructures.It is experimentally demonstrated that the hydrogen production ability of the CuGaS2-ZnS nanoheterostructures(131 ?mol/gh)under visible light irradiation is 15 times higher than that of the CuGaS2 component.The CuGaS2-ZnS heterostructures reduces the rate of electron-hole recombination and more photo-generated electrons would survive.It shows a good reproducibility as evidenced by the recycling hydrogen producing test.